Ok, so if I understood properly:
1) To use a different backing lib, IJavaScriptLibrarySettings's
setWicketEventReference(), setWicketAjaxReference() and
setWicketAjaxDebugReference() methods should be used.
2) If I have a subclass of AbstractDefaultAjaxBehavior which depends on
jQuery, I must still add that dependency in order to "protect" my code
from changes in the backing library.
3) A subclass of JQueryPluginResourceReference will always have a jQuery
dependency no matter what the backing library is.
Blame Emond for that. He changed it and he didn't change the docs in the Wiki...
Ok but I wasn't really looking for someone to blame, but just to
contribute to the beta testing! :)
Thanks for the explanation!